Fix minor deviations between Foreword and ISO/CS standard text. Simplify

list of main changes and remove some more minor items.

Fixes ISO/CS 012 (C++20 DIS).

Author: zygoloid

source/preface.tex

@@ -12,7 +12,7 @@ \chapter{Foreword}
 
 The procedures used to develop this document and those intended for its further
 maintenance are described in the ISO/IEC Directives, Part 1. In particular the
-different approval criteria needed for the different types of documents should
+different approval criteria needed for the different types of document should
 be noted. This document was drafted in accordance with the editorial rules of
 the ISO/IEC Directives, Part 2
 (see \href{http://www.iso.org/directives}{\tcode{www.iso.org/directives}}).
@@ -34,7 +34,7 @@ \chapter{Foreword}
 the meaning of ISO specific terms and expressions related
 to conformity assessment, as well as information about ISO's adherence
 to the World Trade Organization (WTO) principles
-in the Technical Barriers to Trade (TBT) see the following URL:
+in the Technical Barriers to Trade (TBT), see
 \href{http://www.iso.org/iso/foreword.html}{\tcode{www.iso.org/iso/foreword.html}}.
 
 This document was prepared by
@@ -43,21 +43,21 @@ \chapter{Foreword}
 
 This sixth edition cancels and replaces the fifth edition
 (ISO/IEC 14882:2017), which has been technically revised.
-It also incorporates the Technical Specifications
+
+The main changes compared to the previous edition are as follows:
+
+\begin{itemize}
+\item incorporation of the Technical Specifications
 \begin{itemize}
 \item ISO/IEC TS 19217:2015 \textit{Programming Languages --- \Cpp{} Extensions for concepts},
 \item ISO/IEC TS 21425:2017 \textit{Programming Languages --- \Cpp{} Extensions for ranges},
 \item ISO/IEC TS 22277:2017 \textit{Programming Languages --- \Cpp{} Extensions for Coroutines},
 \item ISO/IEC TS 21544:2018 \textit{Programming Languages --- Extensions to \Cpp{} for Modules},
 \item portions of ISO/IEC TS 19571:2016 \textit{Programming Languages --- Technical specification for \Cpp{} extensions for concurrency}, and % latch and barrier
-\item portions of ISO/IEC TS 19568:2017 \textit{Programming Languages --- \Cpp{} Extensions for Library Fundamentals}.
+\item portions of ISO/IEC TS 19568:2017 \textit{Programming Languages --- \Cpp{} Extensions for Library Fundamentals},
 \end{itemize}
-
-The main changes compared to the previous edition are as follows:
-
-\begin{itemize}
 % language changes
-\item addition of concepts, \grammarterm{requires-clause}s, and \grammarterm{requires-expression}s and
+\item addition of concepts, \grammarterm{requires-clause}s, \grammarterm{requires-expression}s, and
 \libheaderref{concepts} header
 \item addition of coroutines, including
 \keyword{co_yield}, \keyword{co_await}, and \keyword{co_return} keywords and
@@ -71,111 +71,43 @@ \chapter{Foreword}
 \item support for optional reason string in \tcode{[[nodiscard]]} attribute
 \item ability to require constant initialization with \keyword{constinit} keyword
 \item ability to require constant evaluation with \keyword{consteval} keyword
-\item extension of constant evaluation support to cover
-\begin{itemize}
-  \item memory allocation and deallocation
-  \item virtual function calls
-  \item \keyword{dynamic_cast} and \keyword{typeid}
-  \item changing the active member of a union
-  \item uninitialized variables
-\end{itemize}
-\item support for constexpr functions to contain
-\keyword{catch} handlers and \grammarterm{asm-declaration}s
-that are not reached during constant evaluation
+\item extensions to constant evaluation
 \item support for controlling destruction in a class-specific operator delete function
 \item addition of \keyword{using} \keyword{enum} declaration
 \item addition of \keyword{char8_t} type
-\item guarantee that \keyword{char16_t} and \keyword{char32_t} literals
-are encoded as UTF-16 and UTF-32 respectively
 \item support for an initializer statement in range-based for loops
 \item support for default member initializers for bit-fields
 \item support for parenthesized aggregate initialization
-\item extended support for lambda expressions, including
-\begin{itemize}
-  \item explicit \grammarterm{template-head}s in generic lambdas
-  \item default construction and assignment of stateless closure types
-  \item lambda expressions in unevaluated operands
-  \item pack expansion of lambda \grammarterm{init-capture}s
-\end{itemize}
-\item generalized support for structured bindings
+\item extensions to lambda expressions
+\item extensions to structured bindings
 \item support for inline namespaces in nested namespace definitions
 \item support for conditionally-explicit member functions
-\item extended support for class template argument deduction to cover
-aggregate initialization and alias templates
+\item extensions to class template argument deduction
 \item reduced cases in which \keyword{typename} is required
 \item support for calling an undeclared \grammarterm{template-id}
 via argument-dependent name lookup
-\item relaxed access checking rules in template specialization declarations
 \item revised memory model
-\item expanded cases in which returned or thrown variables are implicitly moved
 \item extended support for variadic macros with \mname{VA_OPT}
 % library changes
 \item feature test macros and \libheaderref{version} header
-\item restricted valid uses of standard library functions and function templates
 \item addition of ranges and \libheaderref{ranges} header
 \item addition of calendar and time zone support
 \item addition of text formatting library and \libheaderref{format} header
-\item addition of synchronization facilities for
-waiting, notifications, semaphores, latches, and barriers, and
-\libheaderref{barrier}, \libheaderref{latch} and \libheaderref{semaphore} headers
+\item addition of \libheaderref{barrier}, \libheaderref{latch}, and \libheaderref{semaphore} headers
 \item addition of mathematical constants library and \libheaderref{numbers} header
 \item support for representing source locations and \libheaderrefx{source_location}{source.location.syn} header
 \item addition of \tcode{span} view and \libheaderref{span} header
 \item addition of joining thread class and \libheaderrefx{stop_token}{thread.stoptoken.syn} header
-\item extensions to atomic types and operations, including
-\begin{itemize}
-  \item new class template \tcode{atomic_ref}
-  \item new atomic floating-point operations
-  \item new atomic smart pointer types
-  \item support for compare-and-exchange operations on types with padding
-  \item conversion of \tcode{memory_order} to a scoped enumeration
-\end{itemize}
+\item extensions to atomic types and operations
 \item addition of \tcode{unsequenced} execution policy
-\item new utility functions, types, and templates in the standard library, including
-\begin{itemize}
-  \item \raggedright new type traits
-    \tcode{is_bounded_array},
-    \tcode{is_corresponding_member},
-    \tcode{is_layout_compatible},
-    \tcode{is_nothrow_convertible},
-    \tcode{is_pointer_interconvertible_base_of},
-    \tcode{is_pointer_interconvertible_with_class}, and
-    \tcode{is_unbounded_array}
-  \item new transformation traits
-    \tcode{remove_cvref},
-    \tcode{type_identity},
-    \tcode{unwrap_ref_decay}, and
-    \tcode{unwrap_reference}
-  \item new standard library primitive functions \tcode{assume_aligned} and
-    \tcode{is_constant_evaluated}
-  \item new free functions \tcode{erase} and \tcode{erase_if} for containers
-  \item utilities for uses-allocator construction
-  \item function template \tcode{to_address}
-  \item function template \tcode{bind_front}
-  \item function template \tcode{to_array}
-\end{itemize}
-\item \tcode{make_shared} support for array types
-\item support for allocating objects owned by \tcode{shared_ptr} and \tcode{unique_ptr}
-with default initialization
+\item new utility functions, types, and templates in the standard library
 \item addition of bit manipulation library and \libheaderref{bit} header
 \item addition of a synchronized buffered output stream and \libheaderref{syncstream} header
-\item addition of \tcode{shift} algorithms
-\item addition of \tcode{midpoint} and \tcode{lerp} math functions
-\item use of \tcode{[[nodiscard]]} attribute in the standard library
 \item support for heterogeneous lookup for unordered containers
 \item support for element existence detection in associative containers
-\item change to return removed element count
-from \tcode{remove}, \tcode{remove_if}, and \tcode{unique}
-member functions on \tcode{list} and \tcode{forward_list}
-\item addition of \tcode{starts_with} and \tcode{ends_with}
-to \tcode{basic_string} and \tcode{basic_string_view}
 \item support for move semantics in \libheaderrefx{numeric}{numeric.ops.overview} algorithms
 \item support for efficient access to the buffer of a \tcode{basic_stringbuf}
 \item extended constant expression evaluation support in the standard library
-to cover more algorithms, utilities, and types, including
-\tcode{pair}, \tcode{tuple}, \tcode{vector}, and \tcode{string}
-% annexes
-\item removal of deprecated features
 \end{itemize}
 
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